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81.
Naoji Matsumoto Hiroshi Daimon Ju Kumanotani 《Journal of polymer science. Part A, Polymer chemistry》1980,18(6):1665-1678
Cycloalkanone (C5–C8, C12, and C15) or cycloalkane (C5 and C6) ring-containing monomeric diesters and the polyesters derived from them were prepared, and their configurations were studied by 13C-NMR spectroscopy. Absolute configurations were determined for ring sizes 5, 6, and 7. Configurational change during reduction of a ketonic group of monomeric diesters with ring sizes 5 and 6 was discussed in terms of the steric effect of ring substituents on the ketonic group. In the polycondensation reaction epimerization of the ring units was observed in 5-, 6-, and 7-membered cycloalkanones and not in others, which is explained by steric hindrance by the ring substituents against attack of tetrabutyl titanate catalyst on the ketonic group. 相似文献
82.
83.
Taurine is a naturally occurring sulfur-containing amino acid that is found abundantly in excitatory tissues, such as the heart, brain, retina and skeletal muscles. Taurine was first isolated in the 1800s, but not much was known about this molecule until the 1990s. In 1985, taurine was first approved as the treatment among heart failure patients in Japan. Accumulating studies have shown that taurine supplementation also protects against pathologies associated with mitochondrial defects, such as aging, mitochondrial diseases, metabolic syndrome, cancer, cardiovascular diseases and neurological disorders. In this review, we will provide a general overview on the mitochondria biology and the consequence of mitochondrial defects in pathologies. Then, we will discuss the antioxidant action of taurine, particularly in relation to the maintenance of mitochondria function. We will also describe several reported studies on the current use of taurine supplementation in several mitochondria-associated pathologies in humans. 相似文献
84.
A direct, reagent-free, ultraviolet spectroscopic method for the simultaneous determination of nitrate (NO3−), nitrite (NO2−), and salinity in seawater is presented. The method is based on measuring the absorption spectra of the raw seawater range of 200–300 nm, combined with partial least squares (PLS) regression for resolving the spectral overlapping of NO3−, NO2−, and sea salt (or salinity). The interference from chromophoric dissolved organic matter (CDOM) UV absorbance was reduced according to its exponential relationship between 275 and 295 nm. The results of the cross-validation of calibration and the prediction sets were used to select the number of factors (4 for NO3−, NO2−, and salinity) and to optimize the wavelength range (215–240 nm) with a 1 nm wavelength interval. The linear relationship between the predicted and the actual values of NO3−, NO2−, salinity, and the recovery of spiked water samples suggest that the proposed PLS model can be a valuable alternative method to the wet chemical methods. Due to its simplicity and fast response, the proposed PLS model can be used as an algorithm for building nitrate and nitrite sensors. The comparison study of PLS and a classic least squares (CLS) model shows both PLS and CLS can give satisfactory results for predicting NO3− and salinity. However, for NO2− in some samples, PLS is superior to CLS, which may be due to the interference from unknown substances not included in the CLS algorithm. The proposed method was applied to the analysis of NO3−, NO2−, and salinity in the Changjiang (Yangtze River) estuary water samples and the results are comparable with that determined by the colorimetric Griess assay. 相似文献
85.
[reaction: see text] The reactions of aryl aldehydes with styrene derivatives, mediated by various boron Lewis acids, were investigated. 1,3-Dihalo-1,3-diarylpropanes were obtained in high yields with boron trihalides, while 3-chloro-1,3-diarylpropanols were obtained in good to excellent yields with phenylboron dichloride. Reactions involving nonenolizable aliphatic aldehydes, trans-cinnamaldehyde, and beta-substituted styrenes were also investigated for the first time. 相似文献
86.
提出了一种可用于Hg2+快速检测的基于磁纳米颗粒与二段对称分裂式G-四分体DNA酶的生物传感器. 分别用紫外-可见光谱法, 圆二色光谱法和荧光显微镜成像技术对实验设计的DNA酶传感器进行了表征. 传感器中磁纳米颗粒的应用不仅可以直接从水样中通过磁分离方法分离和富集被测物Hg2+, 并且还能将游离的未与Hg2+结合的DNA酶和hemin等除去, 有效地提高检测灵敏度和降低背景信号; 此外, 二段对称分裂式G-四分体DNA酶的运用还可增强传感器的灵活性和选择性. 传感器对Hg2+检测的线性范围为0.8~20 nmol/L, 检出限为0.3 nmol/L. 当水体中的共存离子大量存在时, 传感器对Hg2+的检测仍具有高度特异性. 对实际水样的检测回收率在95.3%~104.4%之间. 实验设计的DNA酶传感器操作简便, 费用低廉, 具有良好的再生能力. 可用于天然水体和饮用水样品中痕量Hg2+的检测. 相似文献
87.
Chunqiao Zhang Yajie Jiang Hongbin Ju Yakui Wang 《Journal of Dispersion Science and Technology》2017,38(12):1817-1823
The obvious different aggregation and adsorption behavior of six newly quaternary ammonium surfactants with different lipophilic counterions has been discoverd by measurements of equilibrium and dynamic surface tension, fluorescence and conductivity. Interestingly, the critical micelle concentration (CMC) and its surface tension γCMC decrease with the increasing counterion chain length. However, three methods have confirmed that an exception of CMC increases slightly from C16NC1 to C16NC2. According to experimental results, a balanced mechanism between hydrophobicity and electrostatic of counterion is proposed. Besides, the dynamic surface tension results show the diffusion coefficient increases with the increasing counterion length both at a short time (Dt?→?0) and long time (Dt?→?∞), which indicates a faster adsorption process. Unlike the inorganic counterion, the diffusion coefficient decreases with the increase of hydrophobic chain length. This is attributed to the strong electrostatic interactions between counterions and cationic headgroups. 相似文献
88.
Dr. Qiang Gao Chuan-Qi Huang Yi-Ming Ju Dr. Min-Rui Gao Dr. Jian-Wei Liu Duo An Dr. Chun-Hua Cui Dr. Ya-Rong Zheng Prof. Dr. Wei-Xue Li Prof. Dr. Shu-Hong Yu 《Angewandte Chemie (International ed. in English)》2017,56(27):7769-7773
Cobalt-based nanomaterials have been intensively explored as promising noble-metal-free oxygen evolution reaction (OER) electrocatalysts. Herein, we report phase-selective syntheses of novel hierarchical CoTe2 and CoTe nanofleeces for efficient OER catalysts. The CoTe2 nanofleeces exhibited excellent electrocatalytic activity and stablity for OER in alkaline media. The CoTe2 catalyst exhibited superior OER activity compared to the CoTe catalyst, which is comparable to the state-of-the-art RuO2 catalyst. Density functional theory calculations showed that the binding strength and lateral interaction of the reaction intermediates on CoTe2 and CoTe are essential for determining the overpotential required under different conditions. This study provides valuable insights for the rational design of noble-metal-free OER catalysts with high performance and low cost by use of Co-based chalcogenides. 相似文献
89.
Hongjuan Liu Shuibo Xie Ju Liao Tianrun Yan Yingjiu Liu Xinhai Tang 《Journal of Radioanalytical and Nuclear Chemistry》2018,317(3):1349-1360
A novel graphene oxide/bentonite composite (GO/bentonite) was synthesized and then characterized through powder X-ray diffraction, fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and energy dispersive spectroscopy. Adsorption achieved equilibrium within 10 min. Moreover, U(VI) adsorption on GO/bentonite was highly dependent on solution pH and independent of ionic strength. These characteristics suggested that inner-sphere surface complexes of U(VI) formed on GO/bentonite. The adsorption of U(VI) from aqueous solution on GO/bentonite was fitted to the pseudo-second-order and Freundlich isotherm models. The maximum sorption capacity of GO/bentonite was 234.19 mg g?1 under neutral pH at 303 K. GO/bentonite is a potentially powerful adsorbent for the efficient removal of U(VI) from aqueous solutions. 相似文献
90.
Elasticity‐Dependent Fast Underwater Adhesion Demonstrated by Macroscopic Supramolecular Assembly 下载免费PDF全文
Guannan Ju Dr. Mengjiao Cheng Fengli Guo Qian Zhang Prof. Feng Shi 《Angewandte Chemie (International ed. in English)》2018,57(29):8963-8967
Macroscopic supramolecular assembly (MSA) is a recent development in supramolecular chemistry to associate visible building blocks through non‐covalent interactions in a multivalent manner. Although various substrates (e.g. hydrogels, rigid materials) have been used, a general design rule of building blocks in MSA systems and interpretation of the assembly mechanism are lacking and are required. Herein we design three model systems with varied elastic modulus and correlated the MSA probability with the elasticity. Based on the effects of substrate deformability on multivalency, we have proposed an elastic‐modulus‐dependent rule that building blocks below a critical modulus of 2.5 MPa can achieve MSA for the used host/guest system. Moreover, this MSA rule applies well to the design of materials for fast underwater adhesion: Soft substrates (0.5 MPa) can achieve underwater adhesion within 10 s with one order of magnitude higher strength than that of rigid substrates (2.5 MPa). 相似文献